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Commit | Line | Data |
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1da177e4 | 1 | /* |
8ca842c4 | 2 | * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com) |
1da177e4 LT |
3 | * Licensed under the GPL |
4 | */ | |
5 | ||
8192ab42 JD |
6 | #include <linux/err.h> |
7 | #include <linux/highmem.h> | |
8 | #include <linux/mm.h> | |
9 | #include <linux/sched.h> | |
10 | #include <asm/current.h> | |
11 | #include <asm/page.h> | |
12 | #include <asm/pgtable.h> | |
1da177e4 | 13 | #include "kern_util.h" |
4fef0c10 | 14 | #include "os.h" |
1da177e4 | 15 | |
ca77b555 | 16 | pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr) |
9157f90f JD |
17 | { |
18 | pgd_t *pgd; | |
19 | pud_t *pud; | |
20 | pmd_t *pmd; | |
9157f90f | 21 | |
ca77b555 JD |
22 | if (mm == NULL) |
23 | return NULL; | |
24 | ||
25 | pgd = pgd_offset(mm, addr); | |
9157f90f | 26 | if (!pgd_present(*pgd)) |
ca77b555 | 27 | return NULL; |
9157f90f JD |
28 | |
29 | pud = pud_offset(pgd, addr); | |
30 | if (!pud_present(*pud)) | |
ca77b555 | 31 | return NULL; |
9157f90f JD |
32 | |
33 | pmd = pmd_offset(pud, addr); | |
34 | if (!pmd_present(*pmd)) | |
ca77b555 | 35 | return NULL; |
9157f90f | 36 | |
ca77b555 | 37 | return pte_offset_kernel(pmd, addr); |
9157f90f | 38 | } |
1da177e4 | 39 | |
ca77b555 | 40 | static pte_t *maybe_map(unsigned long virt, int is_write) |
1da177e4 | 41 | { |
ca77b555 JD |
42 | pte_t *pte = virt_to_pte(current->mm, virt); |
43 | int err, dummy_code; | |
1da177e4 | 44 | |
ca77b555 JD |
45 | if ((pte == NULL) || !pte_present(*pte) || |
46 | (is_write && !pte_write(*pte))) { | |
1da177e4 | 47 | err = handle_page_fault(virt, 0, is_write, 1, &dummy_code); |
8ca842c4 | 48 | if (err) |
ca77b555 JD |
49 | return NULL; |
50 | pte = virt_to_pte(current->mm, virt); | |
1da177e4 | 51 | } |
ca77b555 JD |
52 | if (!pte_present(*pte)) |
53 | pte = NULL; | |
2d58cc9a | 54 | |
ca77b555 | 55 | return pte; |
1da177e4 LT |
56 | } |
57 | ||
47e5243a | 58 | static int do_op_one_page(unsigned long addr, int len, int is_write, |
1da177e4 LT |
59 | int (*op)(unsigned long addr, int len, void *arg), void *arg) |
60 | { | |
8efa3c9d | 61 | jmp_buf buf; |
1da177e4 | 62 | struct page *page; |
ca77b555 | 63 | pte_t *pte; |
8efa3c9d | 64 | int n, faulted; |
1da177e4 | 65 | |
ca77b555 JD |
66 | pte = maybe_map(addr, is_write); |
67 | if (pte == NULL) | |
8ca842c4 | 68 | return -1; |
1da177e4 | 69 | |
ca77b555 | 70 | page = pte_page(*pte); |
8ca842c4 JD |
71 | addr = (unsigned long) kmap_atomic(page, KM_UML_USERCOPY) + |
72 | (addr & ~PAGE_MASK); | |
47e5243a | 73 | |
8efa3c9d JD |
74 | current->thread.fault_catcher = &buf; |
75 | ||
76 | faulted = UML_SETJMP(&buf); | |
77 | if (faulted == 0) | |
78 | n = (*op)(addr, len, arg); | |
79 | else | |
80 | n = -1; | |
81 | ||
82 | current->thread.fault_catcher = NULL; | |
47e5243a | 83 | |
fc0ccfce | 84 | kunmap_atomic((void *)addr, KM_UML_USERCOPY); |
1da177e4 | 85 | |
8ca842c4 | 86 | return n; |
1da177e4 LT |
87 | } |
88 | ||
8efa3c9d JD |
89 | static int buffer_op(unsigned long addr, int len, int is_write, |
90 | int (*op)(unsigned long, int, void *), void *arg) | |
1da177e4 | 91 | { |
8efa3c9d JD |
92 | int size, remain, n; |
93 | ||
1da177e4 LT |
94 | size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len); |
95 | remain = len; | |
96 | ||
47e5243a | 97 | n = do_op_one_page(addr, size, is_write, op, arg); |
8ca842c4 | 98 | if (n != 0) { |
8efa3c9d | 99 | remain = (n < 0 ? remain : 0); |
1da177e4 LT |
100 | goto out; |
101 | } | |
102 | ||
103 | addr += size; | |
104 | remain -= size; | |
8efa3c9d | 105 | if (remain == 0) |
1da177e4 | 106 | goto out; |
1da177e4 | 107 | |
8efa3c9d | 108 | while (addr < ((addr + remain) & PAGE_MASK)) { |
47e5243a | 109 | n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg); |
8ca842c4 | 110 | if (n != 0) { |
8efa3c9d | 111 | remain = (n < 0 ? remain : 0); |
1da177e4 LT |
112 | goto out; |
113 | } | |
114 | ||
115 | addr += PAGE_SIZE; | |
116 | remain -= PAGE_SIZE; | |
117 | } | |
8efa3c9d | 118 | if (remain == 0) |
1da177e4 | 119 | goto out; |
1da177e4 | 120 | |
47e5243a | 121 | n = do_op_one_page(addr, remain, is_write, op, arg); |
8efa3c9d JD |
122 | if (n != 0) { |
123 | remain = (n < 0 ? remain : 0); | |
124 | goto out; | |
125 | } | |
1da177e4 | 126 | |
8efa3c9d JD |
127 | return 0; |
128 | out: | |
129 | return remain; | |
1da177e4 LT |
130 | } |
131 | ||
132 | static int copy_chunk_from_user(unsigned long from, int len, void *arg) | |
133 | { | |
134 | unsigned long *to_ptr = arg, to = *to_ptr; | |
135 | ||
136 | memcpy((void *) to, (void *) from, len); | |
137 | *to_ptr += len; | |
8ca842c4 | 138 | return 0; |
1da177e4 LT |
139 | } |
140 | ||
6aa802ce | 141 | int copy_from_user(void *to, const void __user *from, int n) |
1da177e4 | 142 | { |
8ca842c4 | 143 | if (segment_eq(get_fs(), KERNEL_DS)) { |
1da177e4 | 144 | memcpy(to, (__force void*)from, n); |
8ca842c4 | 145 | return 0; |
1da177e4 LT |
146 | } |
147 | ||
8ca842c4 | 148 | return access_ok(VERIFY_READ, from, n) ? |
1da177e4 | 149 | buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to): |
8ca842c4 | 150 | n; |
1da177e4 LT |
151 | } |
152 | ||
153 | static int copy_chunk_to_user(unsigned long to, int len, void *arg) | |
154 | { | |
155 | unsigned long *from_ptr = arg, from = *from_ptr; | |
156 | ||
157 | memcpy((void *) to, (void *) from, len); | |
158 | *from_ptr += len; | |
8ca842c4 | 159 | return 0; |
1da177e4 LT |
160 | } |
161 | ||
6aa802ce | 162 | int copy_to_user(void __user *to, const void *from, int n) |
1da177e4 | 163 | { |
8ca842c4 JD |
164 | if (segment_eq(get_fs(), KERNEL_DS)) { |
165 | memcpy((__force void *) to, from, n); | |
166 | return 0; | |
1da177e4 LT |
167 | } |
168 | ||
8ca842c4 | 169 | return access_ok(VERIFY_WRITE, to, n) ? |
1da177e4 | 170 | buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) : |
8ca842c4 | 171 | n; |
1da177e4 LT |
172 | } |
173 | ||
174 | static int strncpy_chunk_from_user(unsigned long from, int len, void *arg) | |
175 | { | |
176 | char **to_ptr = arg, *to = *to_ptr; | |
177 | int n; | |
178 | ||
179 | strncpy(to, (void *) from, len); | |
180 | n = strnlen(to, len); | |
181 | *to_ptr += n; | |
182 | ||
8ca842c4 JD |
183 | if (n < len) |
184 | return 1; | |
185 | return 0; | |
1da177e4 LT |
186 | } |
187 | ||
6aa802ce | 188 | int strncpy_from_user(char *dst, const char __user *src, int count) |
1da177e4 LT |
189 | { |
190 | int n; | |
191 | char *ptr = dst; | |
192 | ||
8ca842c4 JD |
193 | if (segment_eq(get_fs(), KERNEL_DS)) { |
194 | strncpy(dst, (__force void *) src, count); | |
195 | return strnlen(dst, count); | |
1da177e4 LT |
196 | } |
197 | ||
8ca842c4 JD |
198 | if (!access_ok(VERIFY_READ, src, 1)) |
199 | return -EFAULT; | |
1da177e4 LT |
200 | |
201 | n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user, | |
202 | &ptr); | |
8ca842c4 JD |
203 | if (n != 0) |
204 | return -EFAULT; | |
205 | return strnlen(dst, count); | |
1da177e4 LT |
206 | } |
207 | ||
208 | static int clear_chunk(unsigned long addr, int len, void *unused) | |
209 | { | |
210 | memset((void *) addr, 0, len); | |
8ca842c4 | 211 | return 0; |
1da177e4 LT |
212 | } |
213 | ||
6aa802ce | 214 | int __clear_user(void __user *mem, int len) |
1da177e4 | 215 | { |
8ca842c4 | 216 | return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL); |
1da177e4 LT |
217 | } |
218 | ||
6aa802ce | 219 | int clear_user(void __user *mem, int len) |
1da177e4 | 220 | { |
8ca842c4 | 221 | if (segment_eq(get_fs(), KERNEL_DS)) { |
1da177e4 | 222 | memset((__force void*)mem, 0, len); |
8ca842c4 | 223 | return 0; |
1da177e4 LT |
224 | } |
225 | ||
8ca842c4 JD |
226 | return access_ok(VERIFY_WRITE, mem, len) ? |
227 | buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len; | |
1da177e4 LT |
228 | } |
229 | ||
230 | static int strnlen_chunk(unsigned long str, int len, void *arg) | |
231 | { | |
232 | int *len_ptr = arg, n; | |
233 | ||
234 | n = strnlen((void *) str, len); | |
235 | *len_ptr += n; | |
236 | ||
8ca842c4 JD |
237 | if (n < len) |
238 | return 1; | |
239 | return 0; | |
1da177e4 LT |
240 | } |
241 | ||
6aa802ce | 242 | int strnlen_user(const void __user *str, int len) |
1da177e4 LT |
243 | { |
244 | int count = 0, n; | |
245 | ||
8ca842c4 JD |
246 | if (segment_eq(get_fs(), KERNEL_DS)) |
247 | return strnlen((__force char*)str, len) + 1; | |
1da177e4 LT |
248 | |
249 | n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count); | |
8ca842c4 JD |
250 | if (n == 0) |
251 | return count + 1; | |
252 | return -EFAULT; | |
1da177e4 | 253 | } |